GCC supports three versions of the C standard, although support for the most recent version is not yet complete. The original ANSI C standard (X3.159-1989) was ratified in 1989 and published in 1990. This standard was ratified as an ISO standard (ISO/IEC 9899:1990) later in 1990. There were no technical differences between these publications, although the sections of the ANSI standard were renumbered and became clauses in the ISO standard. This standard, in both its forms, is commonly known as C89 , or occasionally as C90 , from the dates of ratification. The ANSI standard, but not the ISO standard, also came with a Rationale document. To select this standard in GCC, use one of the options -ansi , -std=c90 or -std=iso9899:1990 ; to obtain all the diagnostics required by the standard, you should also specify -pedantic (or -pedantic-errors if you want them to be errors rather than warnings). See Options Controlling C Dialect . Errors in the 1990 ISO C standard were cor
iso646.h 파일은 일부 연산자에 사용되는 기호들을 사용하기 힘든 환경에서 이를 영문자로 대체하기 위한 목적으로 사용된다. (한글 키보드에서는 이런 문자들이 쉽게 입력 가능하므로 그닭...) 다음과 같이 11가지의 매크로가 정의되어 있다. #define and && #define and_eq &= #define bitand & #define bitor | #define compl ~ #define not ! #define not_eq != #define or || #define or_eq |= #define xor ^ #define xor_eq ^= #include <stdio.h> #include <iso646.h> void alternativeANDOperator ( int num) { const int a = 0; const int b = 10; if (num > a and num < b) { /* num > a && num < b */ printf ( "%d < %d < %d" , a, num, b); } } int main () { int num = 5; alternativeANDOperator(num); return 0; }